Hoisting apparatus



May 22, 1951 L. EAKIN HOISTING APPARATUS 3 Sheets--SheefI l Filed Dec.19, 1947 uer: 10i/1,7201. Elin May 22, 1951 L.. L. EAKIN HoIsTINGAPPARATUS Filed Deo. 19. 1947 5 Sheets-Sheet 2 May 22, 1951 L. L. EAKINHoIsTING APPARATUS 3 Sheets-Sheetl 3 Filed Dec. 19. 1947 apup:

lanzada/1w By i ' ,//HWJ/qy` Patented May 22, 1951 UNITED STATES PATENTOFFICE HOISTING APrARA'rI-Js Lourie L Ea'kin, Ventura, Calif.Application December 19, 1947, lserial No. 792,792

8 Claimsl My invention relates to hoisting apparatus, and particularlyto an apparatus which is especially suitable for installation on atransporting vehicle, such as a motor truck, land having means forhoisting relatively heavy objects and placing them on removing them fromthe platform of the truck. The present invention ris ,concerned with ahoisting apparatus of the lgeneral type disclosed in my pendingapplication for patent on vehicle hoisting apparatus, Serial No.746,248, filed May 6, 1947. The present application embodies novel andimproved actuating means for pivoting the hoist forwardly andrearwardly.

One object of my invention is .to provide a hoisting apparatus whichincludes a boom pivoted on an axis transversely of its platform adjacentone end thereof to adapt it to pivot to an extended position projectingrearwardly from the platform to receive a load which is attached to theend of a ,cable carried by the boom, and to a retracted position toward.the forward end of the platform so that it may be lowered onto theplatform. The invention kfurther provides a novel power-actuated meansfor pivoting the hoisting boom to its different angular positions.

It is -`desirable in hoisting apparatus of this general type that thehoisting boom be adapted to ypivot `througl'i lsubstantially 180degrees, that is, from a horizontal position extending forwardly fromits pivot to a horizontal position projecting rearwardly v.from thetruck, or other vehicle on which the apparatus kmight be installed, sothat the end of the boom may be lowered to a point close to the ground,Vor to the lObject which is to be raised. Itis preferable that hydraulicpower means be employed for pivoting the `looom in order to obtain thepower necessary to .pivot the boom when `relatively heavy .objects arebeing lifted. In such apparatus, it is the nsual practice to operativelyconnect the piston of a hydraulic actuating jack to a relatively shortarm projecting from the pivot of the boom in a downward direction. Sincethe boom moves through substantially 180 degrees the arm liiewise swingsthrough the same angle, land at the extreme vforward and rearwardmovement .of the arm the armand piston approach alignment, and this haslthe effect to cause a substantially deadcenter condition. Due to thiscondition, tremendous amount of vpower is required to obtain themechanical advantage necessary to overcome the weight ofthe Vboom andits supported load.

It is a further object of this invention to pro-- vide means foraugmenting the power yproduced by the usual hydraulic jack at the startof the upward pivoted movement of the boom, so that adequate power isprovided for overcoming inertia of the boom and initiating its upwardtilting movement. This object can be best accomplished by the provisionof auxiliary or secondary fluid-actuated jacks which are operativelyconnected to the pivotal end of the boom only when the latter is at theforward and rearward extremities of its pivotal movement, these jacksthus functioning to assist the main hydraulic jack in overcoming inertiaof the lifting boom. After the boom has been tilted upwardly to aposition wherein a greatly improved mechanical advantage exists.,sufficient power is derived from the main hydraulic jack to .completethe piv` .v otal movement of the boom, and at this lpoint the operationof the auxiliary vjacks :is arrested. By providing a pair of theauxiliary fluidactuated jacks and locating one forwardly and onerearwardly of the pivot of the boom, they may be ,selectively voperatedto assist in initially tilting the boom upwardly from both forward andrearward positions, and this is an important Qbject yof my invention.

is kanother object` of the invention t0 Drovide means for .cushioningthe load when lower.- ing the boom, and, in this respect, I make use of.the auxiliary fluid-actuated pistons which limit ,the downward tiltingmovement of the boom and which maybe actuated in a manner to positively`control the iinal .downward swinging movement, to ease Ithe boom slowlyand safely down,- wardly leven when large loads are sustained thereby.

Another object is to provide, in a hoisting apparatus .of the characterreferred to, a hoisting boom of novel construction, capable `ofsustaining great loads, and one which, when in its forward linoperativeposition, will not interfere with objects located on the truck platformVor other parts of the vehicle.V Preferably, the `boom is of angularshape so that its distal end isadapted to either Yoverlie the ca b ofthe truck', in close Proximity thereto, ,or to be disposed Closelyadvjacent the ,rear side .of the cab when the boom is in Kits vforwardinoperative position, thus avoid- .ing the possibility Yof the `boomprojecting above the truck to a height where it might interferev withthe driving of the vehicle and v,where it might strike trees, wires,bridges, and other overhead objects- ,Further objects of ithe inventionare set forth .in ,the ,fellowing specification which describes severalpreferred embodiments thereof, by way of example, as illustrated by theaccompanying drawings. In the drawings:

Fig. 1 is a side elevational view of a motor truck equipped with oneform of hoisting apparatus, in accordance with my invention;

Fig. 2 is a plan view of the rearward end of the truck, with theplatform thereof removed to disclose the fluid-actuated means foroperating the hoisting boom;

Fig. 3 is a longitudinal sectional view, taken substantially on line 3 3of Fig. 2, and showing the relationship of the parts of the actuatingmeans when the boom is in its forward retracted position;

Fig. 4 is a view similar to Fig. 3, but illustrating the relationship ofthe parts when the boom is in its rearmost, extended position; and,

Fig. 5 is a diagram of the hydraulic circuit for the several liftingjacks.

Referring to the drawings in detail, my improved hoisting apparatus isshown, by way of example,v as installed on a conventional motor truckIIJ, which is provided with a platform for supporting various objectsduring transportation, and a drivers cab I2 mounted on the chassis I3.Fixed to the side rails |4 of the chassis I3 are tubular bearings l5which are adapted to receive a tubular axle or pivot member i6 to adaptthe latter to rotate on an axis extending transversely of the truck,beneath its platform II. Welded or otherwise secured to the ends of thetubular axle I6 are the ends of the arms I9 of a hoisting boom 26. Thearms |9 extend parallel to the lateral edges of the platform I At asuitable distance forwardly of the axle |6 they are inclined upwardlyand inwardly, and then extend substantially horizontally so that theirconvergent ends meet. Through this construction the distal end of theboom is disposed above the cab I2 of the truck in relatively closerelation thereto, to provide compactness and prevent the end fromprojecting upwardly to an extent where it might strike overhead wires,trees, and the like. At the point of joinder of the arms I9, a V-shapedelement is secured, this element being adapted to rotatably support agrooved pulley or sheath 23. A cable 24 passes over the sheath 23 andhas a hook 25 at one end. The other end of the cable 24 is wound aroundthe drum 26 of a power winch, indicated at 21, such means not beingherein shown in detailas they may be of any suitable type generallyemployed in hoisting equipment.

A second pulley or sheath 2| is rotatably mounted between the arms I9 ofthe boom at a point substantially midway between their ends, and thecable 24 may extend around this pulley instead of the pulley 23, ifdesired, as indicated by the heavy dot-and-dash lines in Fig. 1, so thatthe effective length of the boom is decreased. This is advantageous whenlifting certain kinds of objects.

The hoisting boom is adapted to be pivoted to any of the positionsindicated in Figi. 1 by means of fluid-actuated devices, to be nextdescribed. The pivot tube or axle |6 has a pair of spaced radial arms3l) Welded thereto between which is connected the end of a piston rod 3|of a main hydraulic jack 32, the rod 3| being pivotally connected to thearms 36 by a pin 33. The rod 3| carries a piston 34 at its forward end,the piston being slidable in a hydraulic cylinder 35 which is pivotallyconnected to a bracket 36 carried by a cross-member 31 of the vehiclechassis I3. The end of the cylinder 35 is connected by hydraulic lines64 and 5I which lead to a manually-operable valve 38 (Fig. 5), which maybe actuated to selectively introduce fluid under pressure into eitherend of the cylinder to actuate its piston 34 which acts through its rod3| and the arms 30 to turn the pivot tube or axle I6 in either directionto swing the boom 26 between its two extents of movement, illustrated byfull lines and dot-and-dash lines in Fig. 1. While the main hydraulicjack 32 functions to move the boom 2|! through the major portion of itspivotal movement, the movement of the boom at the extreme forward andrearward ends of its movement is controlled by auxiliary fluid-actuatedmeans, to be presently described.

It Will be observed by reference to Figs. 3 and 4 that, when the boom isat th-e extent of its for- Ward and rearward movement, the arms 3Uextend nearly horizontal, and an almost deadcenter relation existsbetween the arms 36 and the piston rod 3|. Because of this veryunfavorable leverage condition, and due to the fact that the greatinertia caused by the heavy boom and the weight supported thereby mustbe overcome, torque of great magnitude must be applied to the axle I6,and, since the moment arm 36 is relatively short, it is apparent thattremendous power is required to produce such force. For this reason itis very desirable, and quite essential, that the mainhydraulic-actuating means be assisted during the start of the pivotalmovement of the boom upwardly from its extended and retracted horizontalpositions. In the present invention this assisting means consists ofauxiliary or secondary fluid-actuated means to be next described.

Pivotally connected to a pin 39 held in a bracket 40 carried by across-strut 4| of the frame I3 is one end of a rst auxiliary hydrauliccylinder 42 in which a piston 43 is slidable. The piston 43 has a rod 44which extends rearwardly and is connected to a pin 45 carried betweenthe ends of a pair of arms 46, which are pivoted on a short shaft 41pivotally mounted in a pair of brackets 4B welded to a cross-member 49of the frame I3 (Fig. 2). The pin 33l has its ends projecting from thesides of the arms 3D, and a finger 56 on the pivot shaft 41 is adaptedto engage one of the projecting ends in the manner to be laterexplained. The cylinder 42 is of the single acting type and, as shown inFig. 5, has only one end connected by a single line 5|a to the selectorvalve 38. When hydraulic fluid is introduced into the cylinder 42, thepiston 43 is moved rearwardly, and thus the arm 46 and the nger 56 arepivoted from the position shown by full lines to the position indicatedby dash-lines in Fig. 3, and, conversely, when the fluid is permitted toescape from the cylinder, the arm and finger move from the dash-lineposition to the full line position.

'Ihe boom-actuating means also includes a second auxiliary cylinder 55which is pivoted on a pin 56 carried by a bracket 51 welded to thecrossmember 49 (Fig. 2). Slidable in the cylinder 55 is a piston 58which has a rod 59 extending forwardly and pivotally connected to a pin66 carried between a pair of arms 6| mounted on a shaft 62 carried bythe bracket 4|). A finger 63 is rotatable With the shaft 62 and adaptedto engage the other projecting end of the pin 33. When the pison 58 isslid forwardly, the arm 6| and nger 63 are pivoted from the positionindicated by double dot-dash line'to that shownl by full lines in Fig.3, and, conversely, when the piston is slid rearwardly the arm and ngerare returned to the first mentioned position. The cylinder 55 is also ofthe single acting type, having a single port connected by a line 64a tothe selector valve 38 (Fig. 5).

The hydraulic system shown in Fig. includes, in addition to the elementsalready described, a reservoir 35, a pump 55, a by-pass valve 61, and apressure-responsive valve 68, connected in the circuit as shown.

Assuming that the boom 2|) is in the position shown by full lines inFigs. l, 2, and 3, with the parts of the actuating mechanism assumingtherelationship shown in Fig. 3, the boom may be pivoted to the rearwardextended position indicated by dot-and-dash lines in Fig. l, and fulllines in Fig. 4, in the manner next explained. By operating the selectorvalve 38, hydraulic uid under pressure is caused to be introduced intothe right-hand or near end of the main cylinder 35 through the line 5|so that the piston rod 3| tends to pivot the arms 3G and boom 20 inclockwise direction. However, due to the fact that at this time analmost dead-center relation exists between the arms 33 and the pistonrod 3|, and because of the fact that the great inertia caused by theheavy boom, and any object supported thereby, must be overcome, torqueof great magnitude must be applied to the axle I5. Since the moment arm30 is relatively short, tremendous power is required to produce theinitial force. In accordance with the present invention, the'mainhydraulic-actuating means is assisted during the start of the upwardpivotal movement of the boom. To effect such assistance, hydraulic uidis introduced into the auxiliary cylinder 42 so that its piston rod 44,acting through the varm 46 and shaft 47|, functions to pivot the arm andfinger 50 from the position shown by full lines to the positionindicated by dash lines in Fig. y3. Inn this manner, the nger 50 actsagainst the pin 33 and thus assists the piston rod 3| in swingingthe arm35 in clockwise direction to move the boom to the position indicated bydash lines in Fig. 3. The movement of the finger 5U is limited, however,by the extent of sliding movement of the piston rod 44 so that it canmove only to the position indicated by dash lines in Fig. 3. However,due to the fact that the -boom 20 is now approaching a verticalposition, less effort or force is required to move the same, and thisforce is readily applied by the main cylinder 35 which now actsindependently.

During the continued rearward pivotal movement, the boom 20 passesacross an imaginary vertical center line drawn through the axle l5. Atthis juncture, force applied by the main cylinder 35 is augmented by agravitational force, and, unless these forces are checked, the boomwould rapidly and violently descend. The valve 53 is employed for thepurpose of controlling such downward pivotal movement of the boom. thevalve being operative, in response to a sudden increase in pressure todecelerate the rate of sliding movement of the piston rod 3|, so as tocontrol the descent of the boom.

When the boom 20 arrives at the position indicated by dot-and-dash linesin Fig. 3, the pin 33 carried by the arm 30 engages against the iinger63 which is, at this time, held in the position shown by dotted lines inFig. 3 by reason of the piston rod 58 being in extended position. Atthis point the selector valve 38 is manipulated to permit fluid to bleedfrom-the cylinder 55, so that the nger 63 and arm 6| move to theposition indicated by double dotdash lines in Fig. 3 to permit the boom20 to descend to its fully extended position, as represented by doubledot-dash lines in Fig. 3 and dotand-dash lines in Fig. l. The boom 20 isthen in position to deposit an object 'IU supported thereby at aconsiderable distance from the rear end of the truck Hl, and the objectcan be lowered by operating the Winch 21. It is thus seen that thepresent boom-operating means maintains positive control over the boom atall times, and by operating the selector valve 38 the boom may bestopped at any desired angle.

To pivot the boom 20 from the fully extended to the fully retractedpositions represented by the respective dot-and-dash and full lines inFig. 1, the operation explained above is reversed. That is to say, themain cylinder or jack 32l and the auxiliary jack cylinder 55 aresimultaneously energized so that the iinger 53 functions to depress thepin 33 and thus move the boom 20 upwardly from the position indicated byfull lines to that represented by dot-and-dash lines in Fig. 4, at whichtime the auxiliary cylinder 55 becomes inactive due to the fact that itspiston rod 59 is fully extended. From this point on the main cylinder 32operates alone to swing the boom 2|) forwardly until the latter reachesthe position shown by dash lines in Fig. 4, the valve 58 functioning tocontrol such movement as the boom passes a vertical position.

Upon reaching the dash-line position in Fig. 4, the pin 33 engages thefinger 50 of the arm 46, which is maintained in the position shown byfull lines in Fig. 4 by the fully extended piston rod 43. To lower theboom 20 to the position shown by double dot-dash lines in Fig. 4, thepiston rod di is retracted into the auxiliary cylinder l2 so that thefinger 5i! is pivoted to the position indicated by double dot-dash linesin Fig. It will be understood that by manipulating the valve 33 the boom25 can be brought to rest at any point intermediate its extended andretracted positions, such as the position indicated by the dash lines inFig. l, so that the object 'l0 can be lowered onto the truck platform atany desired location While the object Hl herein shown is one which maybe set upon the platform, it will be apparent that the boom 25 iscapable of lifting and supporting other objects, such as poles, inupright position, to permit them to be erected in holes in the ground.The hoisting apparatus may thus be said to be universal in itsapplication to use, and may be advantageously employed on transportationand con-struction vehicles. Moreover, the hoisting equipment may bereadily applied to existing trucks with minimum change in theirstructures.

While I have herein shown and described the improved hoisting apparatus,as embodied in a preferred form of construction and applied to use witha particular type of vehicle, by way of example, it will be apparentthat the construction of the apparatus and its application to use may bevaried in certain respects, in association with a vehicle, or othermeans or mechanisms, without departing from the spirit or scope of theinvention. Therefore, without limiting myself in this respect, I claim:

l. In an apparatus of the class described, comprising: a support; a boompivoted transversely a pivot pin; primary actuating means connected tosaid pin and operable to pivot said arm and said boom through the majorportion of their movement in either direction; a pair of fingers movableforwardly and rearwardly of the pivot of Said boom and adapted to engageand move said pivot pin lwhen moved so as to pivot said boom; and a pairof secondary actuating means pivoted on said support forwardly andrearwardly of the pivot of said boom and operatively connected to saidfingers so as to pivot the same during the initial actuation of saidprimary actuating means so as to assist said primary actuating means inraising said boom.

2. In an apparatus of the class described, comprising: a support; a boompivoted transversely of the support to adapt it to pivot to a forwardposition overlying the support, to a rearward position projectingrearwardly from the support, and to position intermediate said forwardand rearward positions said boom having an arm projecting from itspivotal end and provided with a pivot pin; primary fluid-actuating meansconnected to said pin and operable to pivot said arm and said boomthrough the major portion of their movement in either direction; and apair of secondary fluid-actuating means pivoted on said supportforwardly and rearwardly of the pvot of said boom and adapted to engageand move said pivot pin during the initial actuation of said primaryactuating means so as to assist said primary actuating means in raisingsaid boom.

3. In an apparatus of the class described, comprising: a support; a boompivoted transversely of the support to adapt it to pivot to `a forwardposition overlying the support, to a rearward position projectingrearwardly from the support, and to positions intermediate said forwardand rearward positions, said boom having an arm projecting from itspivotal end and provided with a pivot pin; primary fiuid-actuating meansconnected to said pin and operable to pivot said arm and said boomthrough the major portion of their movement in either direction; a pairof fingers movable forwardly and rearwardly of the pivot of said boomand adapted to engage and move said pivot pin when moved so as to pivotsaid boom; and a pair of secondary uid-actuating means pivoted on saidsupport forwardly and rearwardly of the pivot of said boom andoperatively connected to said fingers so as to pivot the same during theinitial actuation of said primary actuating means so as to assist saidprimary actuating means in raising said boom.

4. In an apparatus of the class described, comprising: a support; a boompivoted transversely of the support to adapt it to pivot to a forwardposition overlying the support, to a rearward position projectingrearwardly from the support, and to positions intermediate said forwardand rearward positions, Asaid boom having an arm projecting from itspivotal end and provided with a pivot pin; primary actuating meansconnected to said pin and operable to pivot said arm and said boomthrough the major portion of their movement in either direction; a pairof fingers pivotally mounted forwardly and rearwardly of the pivot ofsaid boom and adapted to engage and move said pivot pin, upon pivotalmovement, so as to pivot said boom; and a pair of secondary actuatingmeans pivoted on said support forwardly and rearwardly of the pivot ofsaid boom and operatively connected, respectively, to said fingerspivoted rearwardly and forwardly of said pivot of said boom so as topivot the finger during the initial actuation of said primary actuatingmeans so as to assist said primary actuating means in raising said boom.

5. In an apparatus of the class described, comprising: a support; a boompivoted transversely of the support to adapt it to pivot to a forwardposition overlying the support, to a rearward position projectingrearwardly from the support, and to positions intermediate said forwardand rearward positions, said boom having an arm projecting from itspivotal end and provided with a pivot pin; primary actuating meansconnected to said pin and operable to pivot said arm and said boomthrough the major portion of their movement in either direction; shaftspivoted forwardly and rearwardly of the pivot of said boom; fingerscarried by each of said shafts and adapted to engage and move said pivotpin, upon pivotal movement of each of said shafts, so as to pivot saidboom; secondary actuating means pivoted on said support; and armscarried by said shafts and connected to said secondary actuating meansso that said shaft and said fingers` are pivoted during the initialactuation of said primary actuating means to assist said primaryactuating means in raising said boom.

6. A hoisting means as dened in claim 2, and including: a fluid systemfor said fluid-actuating means, said system having pressure-inducingmeans, selector valve means, for controlling the introduction into anddischarge of fluid from each of said actuating means, andpressure-responsive valve means automatically operative, when said boompasses a vertical position during its pivotal movement in a forward orrearward direction, to control the rate of flow of fluid into and fromsaid primary actuating means so as to prevent a rate of pivotal movementof said boom in excess of a predetermined rate.

' 7. In an apparatus of the class described, having: a support; a boompivoted transversely of the support to adapt it to pivot to a forwardposition overlying the support, to a rearward position projectingrearwardly from the support, and to positions intermediate said forwardand rearward positions, said boom having an arm projecting from itspivotal end and provided with a pivotpin; a primary fluid-actuatedcylinder pivotally mounted forwardly of the pivot of said boom andconnected to said pin so as to pivot said arm and said boom through themajor portion of their movement in either direction; a pair of secondaryfluid-actuated cylinders pivoted forwardly and rearwardly of said boompivot and adapted to engage and move said pivot pin during the initialactuation of said primary actuating cylinder so as to assist saidprimary actuating cylinder in raisng said boom: a fluid system for allof said actuating cylinders; and valve means in said system forcontrolling the actuation of all of said actuating cylinders in a mannersuch that simultaneous actuation of said primary actuating cylinder andeither of said secondary actuating cylinders is effected.

8. In an apparatus of the class described, comprising: a support; a boompivoted transversely of the support to adapt it to pivot to a forwardposition overlying the support, to a rearward 9 position projectingrearwardly from the support, and to positions intermediate said forwardand rearward positions, said boom having Aan arm projecting from itspivotal end and provided with a pivot pin; primary actuating meansconnected 5 to said pin and operable to pivot said arm and said boomthrough the major portion of their movement in either direction; and asecondary actuating means spaced from the pivot of said koom 4andpivoted on said support, said secondary actuating means being adapted toengage and move fsaid pivot pin during initial actuation of said primaryactuating means so as to assist said primary actuating means in raisingsaid boom.

LOURIE L. EAKIN.

10 REFERENCES CITED The following references are of record in the fileof this patent:

UNITED STATES PATENTS

